I spent a good part of last year muddling through classes with a pretty nasty break in my ankle that took so fucking long to heal,I kept training anyway,& yeah,if someone was a lower rank,I had no problem at all asking them not to sweep my lead leg if they caught a kick.
I made it quite clear that I was more than happy for them to bang in an overhand right & knock me out,just don't sweep unless you're really fucking good at it as it was a shitty sweep attempt that broke it in the first place.

I don't see why people who don't want to spar are supposed to be stigmatized in your classes.

I made up excuses for not doing homework. If I don't want to spar, I'm not going to spar. I don't owe you an 'excuse' for something I'm not obligated to do.

"That was the only way you could destroy me. Neither do I quail at death nor act in deference to any god. So drop your talk, I come resolved to die. But first, there are these gifts I bring for you." At once he hurled a javelin at his enemy, then sent another and another still straight to the mark. - Virgil's The Aeneid